chore: import style files

Following `dartsass-rails` documentation.

In particular this section of the README.
https://github.com/rails/dartsass-rails/blob/5c88f1ba7287900b81385c17c1a69556833b401a/README.md?plain=1#L7

app/assets/stylesheets/application.scss

@@ -1,20 +1,12 @@
-/*
- * This is a manifest file that'll be compiled into application.css, which will include all the files
- * listed below.
- *
- * Any CSS and SCSS file within this directory, lib/assets/stylesheets, or any plugin's
- * vendor/assets/stylesheets directory can be referenced here using a relative path.
- *
- * You're free to add application-wide styles to this file and they'll appear at the bottom of the
- * compiled file so the styles you add here take precedence over styles defined in any other CSS/SCSS
- * files in this directory. Styles in this file should be added after the last require_* statement.
- * It is generally better to create a new file per style scope.
- *
- *= require_tree .
- *= require_self
- */
-
-@import "reset";
+@use "reset";
+@use "_fonts";
+@use "_footer";
+@use "_forms";
+@use "_google_sso";
+@use "_rating";
+@use "_search";
+@use "_utility";
+@use "welcome_banner";
 
 body {
   display: flex;